Which of the following relations is not a function?

A. { (0,1), (1,1), (2,1), (3,1)}
B. { (0,0), (3,4), (5,6), (8,9)}
C. { (0,1), (0,2), (0,3), 0,4)}
D. { (0,0), (2,2), (4,4), (6,6)}

C

Step-by-step explanation:

The X values repeat so its not a function

18

step-by-step explanation:

draw the shape and you will see that f and k are actually at adjacent vertices (points of the hexagon that are neighboring).   so find the distance between (1,2) and (4,2).   that is easy since (1,2) and (4,2) is just a vertical distance to count, which is 3.   it is a regular polygon which means all sides are congruent.   you have 6 sides (hexa) so multiply 6 by 3 to receive 18.